The present invention relates to methods of and apparatus for the generation of radio-frequency pulses or continuous waves in antenna resonator circuits or similar tuned circuits through excitation by sequential pulses, being particularly useful for the generation of bursts of radio-frequency energy as for Loran-C or similar radio navigation or other pulses, or for continuous waves in resonant loads or similar systems.
The generation of such high power radio frequency pulses by successive positive and negative half-cycle d.c. pulses for such navigation pulse generation is described, for example, in U.S. Pat. No. 3,889,263; and such generation may be effected by a plurality of SCR-controlled sequential inverters connected with magnetic pulse compression circuits feeding the common high-Q antenna load as in U.S. Pat. Nos. 3,711,725 and 3,786,334.
While such systems work admirably well in practice, it has now been discovered that similar operation can be successfully obtained with much fewer required sequential inversions and otherwise less costly apparatus, and/or with excitation by fewer d.c. pulses or half-cycles that are relatively narrow and widely spaced, instead of broad and more contiguous as in the prior systems. Additionally, this technique is well suited for the generation of high power CW transmissions, particularly in the VLF band as, for example, 50 to 30 kHz.